It is a text messager plus a wakie talkie. In a simply word, you can send text message and also a voice message.
I am sure there are same type of App out there, but what make WEIXIN different is you need to sign in as a member to be able to do it. The reason for that is so you can sent free text message and voice message international.
Since I download this App, I have been talking with my family back in China free~~~!!!
It is great~~~!!
Oh, and it works with Iphone and another smart phones. So, go get one and let's talk~~~!!